What does everyone use? I use mostly prepackaged meals that call for a very specific amount of water and don't really want to experiment with alternate amounts. Carrying a measuring cup seems like a waste. I have tried marking a container that I use for other things, but it doesn't last (used a sharpie).

So, I'm trying to find out what everyone uses. I assume that most everyone measures water (maybe a bad assumption, but…), so, what do you use?

I use Sharpie. Find a place where there's an indent so it doesn't get rubbed off. Still, it gets rubbed off after a while so I re-do the mark. The plastic bottle should be replaced occasionally anyway. Not a perfect solution like you've concluded.

I use either a Snow Peak 600 pot or an MSR Titan Kettle, and I have scored lines in them with a Dremel disk to denote 1.0, 1.5, and 2.0 cups. This makes it pretty easy to pour the right amount into my FD meal bags. I usually pour 1.5 cups into my Pro Packs, stir well, then add a smidge more to thin it slightly (I don't care much for thick and gloppy meals).

Since all my pots seem to have ml indentations and no cup markings, I just pour in one cup of water and scratch a line on the inside of the pot (with a pocket knife, screw driver, fork, whatever). Repeat at two cup measurement. No problems with marks disappearing, takes a minute to do.

There's a bucket of wine and a bucket of water and you transfer a cup of wine to the water bucket, and then a cup of the mixture back to the wine bucket. Is there more wine in the water or water in the wine?

DO NOT Google the answer. Work it around in your head, and explain your reasoning.

Going back to measuring…
My pot holds 500ml at about 1cm from the top.
Half of that is 250ml or 1 cup. so one quater of my pot is about 125ml or half a cup.
All of the above are good enough for me to figure out how much water I need.

E.g. each bucket has 1 cup of liquid to start:
1. The wine bucket becomes empty, with 2 cups in the water bucket, 1:1 mix.
2. The water bucket is reduced back to 1 cup, 1:1 mix.
3. The wine bucket once more has 1 cup of the 1:1 mix.
Thus, the buckets are equal.

So, it doesn't seem to matter; they are the same. I think I see a relationship with the water:wine ratio being the inverse of what's needed to balance out the other bucket. Since the ratio for the water bucket is calculated with an extra cup of liquid (e.g. 9:1 rather than 8:1, which means a 90% solution rather than an 88.9% solution), the cup being added back to the wine bucket needs to reflect that offset in some way. What did I miss?

Let the water bucket be huge, and the wine bucket small – so small it holds just one cup of wine.
Transfer 1 cup of wine to the water bucket. Now there is no wine in the wine bucket.
Transfer 1 cup of water/wine mix back to the wine bucket. Now there is a very small amount of wine in the wine bucket, and all the rest of the cup-full in the water bucket.

Alternately, let the water bucket be tiny and the wine bucket huge …

I suggest the problem is so poorly defined that any answer could be correct.

Some really great ideas here (I knew there would be). I got one of those really light SS pots from Sierra Trading Post and I think I will use the center punch method, unless I can find my Dad's dremel. I need to find that thing, seems like there is always something I want it for. :^)

Thanks for the ideas. Next time I want to use a plastic container I have several new ideas to try!

Extending my "solution", as long as each bucket starts with at least 1 cup of liquid, this shouldn't actually matter; in each case the amount of wine added to the water bucket should equal the amount of water added to the wine bucket.

E.g. if you start with 1 cup of wine and 9 cups of water, you still end up with 0.9 cups of water in the wine bucket and 0.9 cups of wine in the water bucket.